JP5159365B2 - Semiconductor device and manufacturing method thereof - Google Patents
Semiconductor device and manufacturing method thereof Download PDFInfo
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- JP5159365B2 JP5159365B2 JP2008044392A JP2008044392A JP5159365B2 JP 5159365 B2 JP5159365 B2 JP 5159365B2 JP 2008044392 A JP2008044392 A JP 2008044392A JP 2008044392 A JP2008044392 A JP 2008044392A JP 5159365 B2 JP5159365 B2 JP 5159365B2
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- 239000004065 semiconductor Substances 0.000 title claims description 40
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 238000009792 diffusion process Methods 0.000 claims description 38
- 239000000758 substrate Substances 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 9
- 239000012535 impurity Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000000059 patterning Methods 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- OKZIUSOJQLYFSE-UHFFFAOYSA-N difluoroboron Chemical compound F[B]F OKZIUSOJQLYFSE-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
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- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
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- H01L29/1025—Channel region of field-effect devices
- H01L29/1029—Channel region of field-effect devices of field-effect transistors
- H01L29/1033—Channel region of field-effect devices of field-effect transistors with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure
- H01L29/1037—Channel region of field-effect devices of field-effect transistors with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure and non-planar channel
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- H01L29/0615—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE]
- H01L29/0619—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions for preventing surface leakage or controlling electric field concentration for increasing or controlling the breakdown voltage of reverse biased devices by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
- H01L29/0623—Buried supplementary region, e.g. buried guard ring
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- H01L29/1025—Channel region of field-effect devices
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- H01L29/1033—Channel region of field-effect devices of field-effect transistors with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure
- H01L29/1041—Channel region of field-effect devices of field-effect transistors with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure with a non-uniform doping structure in the channel region surface
- H01L29/1045—Channel region of field-effect devices of field-effect transistors with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure with a non-uniform doping structure in the channel region surface the doping structure being parallel to the channel length, e.g. DMOS like
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- H01L29/4232—Gate electrodes for field effect devices for field-effect transistors with insulated gate
- H01L29/42356—Disposition, e.g. buried gate electrode
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Description
本発明は、半導体装置およびその製造方法に関する。特に、トレンチを有するMOSトランジスタに関するものであり、埋め込み層を用いて駆動能力の向上を図るものである。 The present invention relates to a semiconductor device and a manufacturing method thereof. In particular, the present invention relates to a MOS transistor having a trench, and uses a buried layer to improve driving capability.
MOSトランジスタは電子部品において中核を担う素子であって、MOSトランジスタの小型化、低消費電力あるいは高駆動能力化は、重要な課題となっている。MOSトランジスタを高駆動能力化する方法の1つとして、ゲート幅を広くしてオン抵抗を低減させる方法があるが、ゲート幅を広くするとMOSトランジスタの占有面積が大きくなるという問題があった。そこで、これまでにもトレンチを利用してMOSトランジスタの専有面積の増加を抑えながらゲート幅を広くする技術が提案されている。 MOS transistors are the core elements of electronic components, and miniaturization, low power consumption, and high drive capability of MOS transistors are important issues. One method for increasing the driving capability of a MOS transistor is to increase the gate width to reduce the on-resistance, but there is a problem that the area occupied by the MOS transistor increases when the gate width is increased. Thus, there has been proposed a technique for widening the gate width while suppressing an increase in the area occupied by the MOS transistor by using a trench.
従来の半導体装置について図4を基に説明する。 A conventional semiconductor device will be described with reference to FIG.
図4(A)の斜視図に示すように、MOSトランジスタ幅方向(W方向)にトレンチ13を有しており、表面でのゲート電極15の幅に対して、実効的なゲート幅の長さが長くなるので、MOSトランジスタの耐圧を低下させずに単位面積あたりのオン抵抗を低減することができる。
As shown in the perspective view of FIG. 4A, the
図4(B)はそのMOSトランジスタの平面模式図である。トレンチ13の断面をA-A'、トレンチ13を有しない領域の断面をB-B'として、断面図を図4(C)および図4(D)にそれぞれ示す。図4(C)に示される領域は通常のプレーナー型MOSトランジスタになるので、電流がソース高濃度拡散層16からドレイン高濃度拡散層17に流れる場合には、電流経路は図中矢印Aのようになる。一方で、トレンチ13を有する図4(D)に示される領域ではMOSトランジスタ幅方向の奥行き側面において電流は矢印B、底部においては矢印Cで得られる。(例えば、特許文献1参照)
しかしながら、従来技術では、より高駆動能力化を目指すためにトランジスタのL長を縮小する場合、実効的なチャネル長の距離の差が顕著になり、図4(D)の経路Cと図4(C)の経路Aでは、経路Aで示される平面領域が支配的になり、底部Cではほとんど流れなくなる。これにより、トレンチ13を深く形成して実効的なゲート幅の長さを長くしてオン抵抗を減少させる策をとっても、駆動能力が得られないという問題がある。あわせて、トランジスタのゲート長さ(L方向)を縮小できないため、面積を縮小できない障害も生じてしまう。
However, in the conventional technique, when the L length of the transistor is reduced in order to achieve higher driving capability, the difference in effective channel length distance becomes significant, and the path C in FIG. In the route A of C), the plane area indicated by the route A becomes dominant, and almost no flow occurs at the bottom C. As a result, there is a problem in that the driving ability cannot be obtained even if the
このように、図4(A)の構造では、トレンチの深さを深くする、あるいはゲート幅(W方向)を縮小させて実効的なゲート幅を長くしても、ゲート長さ(L長方向)を縮小できないため、想定したよりも駆動能力が得られない、さらには、トランジスタの面積縮小ができないという問題がある。これは、L長の縮小でトレンチ上面、側面および底面での実効的なチャネル長距離の差が顕著になってしまい、優先的にトレンチ上面で電流が流れやすくなるので、トレンチを有する特徴である底面での電流が減少するためである。 Thus, in the structure of FIG. 4A, even if the trench depth is increased or the gate width (W direction) is reduced to increase the effective gate width, the gate length (L length direction) ) Cannot be reduced, the driving ability cannot be obtained more than expected, and the area of the transistor cannot be reduced. This is a feature of having a trench because the reduction in L length makes the difference in effective channel length distance on the top, side and bottom surfaces of the trench noticeable, and current flows preferentially on the top surface of the trench. This is because the current at the bottom surface decreases.
そこで、本発明の目的は、トレンチを有する半導体装置のMOSトランジスタのL長を縮小してもトレンチ底面での電流経路が確保でき、想定した駆動能力が得られるようにすること、つまり駆動能力の減少を抑制することである。 Therefore, an object of the present invention is to ensure a current path at the bottom of the trench even when the L length of the MOS transistor of the semiconductor device having a trench is reduced, and to obtain an assumed drive capability, that is, drive capability. It is to suppress the decrease.
上記課題を解決するために、本発明は次の手段を用いた。
(1)第1導電型半導体基板と、前記第1導電型半導体基板上の所定の領域に形成された第2導電型埋め込み層と、前記第2導電型埋め込み層および前記第1導電型半導体基板の上に形成された第1導電型エピタキシャル成長層と、前記第1導電型エピタキシャル成長層に形成された、形成されるトランジスタのゲート幅方向に並んで配置された、その底部は前記第2導電型埋め込み層に達するトレンチと、ゲート絶縁膜を介して前記トレンチの内部及び上面と前記トレンチに隣接する第1導電型エピタキシャル成長層の表面部分に形成されたゲート電極と、前記ゲート電極の一方の側に形成された第2導電型のソース高濃度拡散層と、前記ゲート電極の他方の側に形成された第2導電型のドレイン高濃度拡散層と、を有する半導体装置とした。
(2)第1導電型半導体基板の所定の領域に第2導電型埋め込み層を形成する工程と、前記第2導電型埋め込み層および前記第1導電型半導体基板の上に第1導電型エピタキシャル成長層を形成する工程と、前記第1導電型エピタキシャル成長層に、形成されるトランジスタのゲート幅方向に並んで、その底部が前記第2導電型埋め込み層に達するようにトレンチを形成する工程と、ゲート絶縁膜を形成する工程と、前記ゲート絶縁膜を介して前記トレンチの内部及び上面と前記トレンチに隣接する第1導電型エピタキシャル成長層の表面部分にゲート電極を形成する工程と、前記ゲート電極の一方の側に第2導電型のソース高濃度拡散層、他方の側に第2導電型のドレイン高濃度拡散層とを形成する工程と、を含む半導体装置の製造方法とした。
In order to solve the above problems, the present invention uses the following means.
(1) A first conductivity type semiconductor substrate, a second conductivity type buried layer formed in a predetermined region on the first conductivity type semiconductor substrate, the second conductivity type buried layer, and the first conductivity type semiconductor substrate The first conductivity type epitaxial growth layer formed on the first conductivity type epitaxial growth layer and the transistor formed on the first conductivity type epitaxial growth layer are arranged side by side in the gate width direction. A trench reaching the layer, a gate electrode formed on the inside and upper surface of the trench and a surface portion of the first conductivity type epitaxial growth layer adjacent to the trench via a gate insulating film, and formed on one side of the gate electrode A second conductive type high concentration source diffusion layer and a second conductive type high concentration drain layer formed on the other side of the gate electrode. .
(2) forming a second conductive type buried layer in a predetermined region of the first conductive type semiconductor substrate; and a first conductive type epitaxial growth layer on the second conductive type buried layer and the first conductive type semiconductor substrate. Forming a trench in the first conductivity type epitaxial growth layer so as to be aligned in the gate width direction of the transistor to be formed so that the bottom portion reaches the second conductivity type buried layer, and gate insulation A step of forming a film, a step of forming a gate electrode inside and on the upper surface of the trench and a surface portion of the first conductivity type epitaxial growth layer adjacent to the trench through the gate insulating film, and one of the gate electrodes Forming a second conductivity type source high-concentration diffusion layer on the side and a second conductivity type drain high-concentration diffusion layer on the other side, and a method for manufacturing a semiconductor device, It was.
本発明は、トレンチを有するMOSトランジスタのL長を縮小しても駆動能力の減少を抑制可能であるという特徴である。トランジスタのL長と同じ距離かそれより短い距離の深さのトレンチを有すること、さらにトレンチの底部に埋め込み層を用いることで、ソース高濃度拡散層下端あるいはドレイン高濃度拡散層下端からトレンチ底面までの実効的なチャネル長を最短L長のトレンチ上面よりも短くすることである。これによって、上記ソースあるいはドレインの高濃度拡散層に接する側面から埋め込み層を用いてトレンチ底面での電流経路を保持させることで駆動能力を向上させる。したがって、ゲート長が縮小された場合でも駆動能力の減少を抑制する効果がある。 The present invention is characterized in that a reduction in driving capability can be suppressed even if the L length of a MOS transistor having a trench is reduced. By having a trench with a depth equal to or shorter than the L length of the transistor and using a buried layer at the bottom of the trench, from the bottom of the source high-concentration diffusion layer or the bottom of the drain high-concentration diffusion layer to the bottom of the trench Is to make the effective channel length shorter than the shortest L-long trench upper surface. Thus, the driving capability is improved by maintaining the current path at the bottom of the trench using the buried layer from the side surface in contact with the high concentration diffusion layer of the source or drain. Therefore, even when the gate length is reduced, there is an effect of suppressing a decrease in driving capability.
以下、本発明の実施の形態を図面に基づいて説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
図1は本発明の第1の実施例の半導体装置を示す模式図である。図1(A)はトレンチ6を有するMOSトランジスタの平面模式図である。図中のトレンチ6以外のプレーナー型トランジスタの構造にあたるA-A'に沿った断面模式図を図1(B)に示す。図中のトレンチ6のB-B'に沿った断面模式図を図1(C)に示す。図1(B)では、第1導電型の半導体基板1の上の所定の領域にのみ部分的に第2導電型の埋め込み層2が形成され、その上には半導体基板と同じ導電型のエピタキシャル成長層3が形成されている。エピタキシャル成長層3の上表面にはゲート酸化膜7を介してゲート長がLであるゲート電極8が設けられている。そして、ゲート電極8のゲート長Lだけ離れて対面する領域には、一方の領域に第2導電型のソース高濃度拡散層9、そして他方には第2導電型のドレイン高濃度拡散層10が形成される。この場合のソース高濃度拡散層9とドレイン高濃度拡散層10との間の電流経路は図中の矢印Aである。
FIG. 1 is a schematic diagram showing a semiconductor device according to a first embodiment of the present invention. FIG. 1A is a schematic plan view of a MOS transistor having a
図1(C)はトレンチ6を有する領域の断面図であり、第1導電型の半導体基板1の上に部分的に第2導電型の埋め込み層2が形成され、その上には半導体基板と同じ導電型のエピタキシャル成長層3が形成されている。エピタキシャル成長層3にはトレンチ6が埋め込み層2に接するように設けられている。ゲート長方向で埋め込み層2とトレンチ6の長さを比較すると、埋め込み層2の長さはトレンチ6の長さと同等以上であれば良い。トレンチ6の側面にはソース高濃度拡散層9およびドレイン高濃度拡散層10が形成され、トレンチ6内面とソース高濃度拡散層9表面とドレイン高濃度拡散層10表面にはゲート絶縁膜7が設けられており、トレンチ6の中にはゲート電極8が充填されている。この構造では、矢印Bで示す電流経路と、ソース高濃度拡散層9から矢印Dから埋め込み層2を経由して矢印Eからドレイン高濃度拡散層10に至る電流経路(以下、電流経路C'と呼ぶ)が考えられる。このとき、ソース高濃度拡散層9と埋め込み層2との距離(=ドレイン高濃度拡散層10と埋め込み層2との距離)がゲート長と同等以下の長さであれば、電流経路C'にも電流が流れやすくなる。このようにすることで、MOSトランジスタの駆動能力を向上させることができる。
FIG. 1C is a cross-sectional view of a region having a
図2は第1の実施例の半導体装置を製造するための工程フロー図である。ここでは、図1(C)に対応する断面図を用いて説明する。 FIG. 2 is a process flow diagram for manufacturing the semiconductor device of the first embodiment. Here, description is made with reference to a cross-sectional view corresponding to FIG.
図2(A)において、まず第1導電型半導体基板、例えばP型半導体基板1、例えばホウ素添加した抵抗率20Ωcmから30Ωcmの不純物濃度の半導体基板の所定の領域に、第2導電型埋め込み層2を、例えばN型埋め込み層であれば砒素、燐、アンチモンなどの不純物を用いて濃度は例えば1×1018atoms/cm3程度の濃度くらいから1×1021atoms/cm3程度で形成する。なお、第2導電型埋め込み層2が例えばP型埋め込み層ならホウ素などの不純物を用いれば良い。次いで、埋め込み層2を間に挟むように、半導体基板1と埋め込み層2の上に第1導電型エピタキシャル成長層3を形成する。成長層の膜厚は例えば数μmから数十μmである。エピタキシャル成長層3の表面にはLOCOS法によりLOCOS酸化膜4を形成させる。
In FIG. 2A, first, a second conductivity type buried
次に図2(B)に示すように、トレンチエッチングのためにマスク5でパターニングをおこなう。このマスク5は、例えば膜厚は数十nm〜数百nmの熱酸化膜、あるいは膜厚は数百nm〜1μmとした堆積酸化膜のどちらでも可能であり、熱酸化膜および堆積酸化膜の積層構造でも可能である。さらに、マスク5はレジスト膜あるいは窒化膜でも問題はない。パターニングされたマスク5を用いてエッチングによりトレンチ6を形成する。このとき、トレンチ6は埋め込み層2に接するように形成する。その後マスク5を除去した後、図2(C)に示すようにゲート絶縁膜7、例えば膜厚が数百〜数千Åの熱酸化膜を形成する。さらにここでは、上述の第2導電型埋め込み層2の濃度が中濃度から高濃度程度の場合、第2導電型埋め込み層2の表面において熱酸化膜厚が厚くなることから、自動的にゲート絶縁膜7と第2導電型埋め込み層2間での容量を低減させることが可能である。
Next, as shown in FIG. 2B, patterning is performed with a mask 5 for trench etching. The mask 5 can be, for example, a thermal oxide film having a film thickness of several tens of nm to several hundreds nm, or a deposited oxide film having a film thickness of several hundred nm to 1 μm. A laminated structure is also possible. Further, there is no problem even if the mask 5 is a resist film or a nitride film. A
次に、図2(D)に示すように多結晶シリコンゲート膜を好ましくは膜厚を100nm〜500nmで堆積し、プリデポあるいはイオン注入法により不純物を導入してゲート電極8とする。ここでの導電型は例えば第1導電型でも第2導電型でも可能である。それにレジスト膜9でパターニングして、図2(E)に示すようなトレンチ6を有するトランジスタ構造が整う。引き続き、図2(E)に示すように、セルフアライン法でソース領域およびドレイン領域を形成するための不純物添加を行う。ここでのセルフアライン法は本発明の本質とは関係ない。ソース領域およびドレイン領域の不純物添加は例えば導電型がN型なら例えば砒素あるいは燐を好ましくは1×1015atoms/cm2から1×1016atoms/cm2のドーズ量でイオン注入する。一方で、導電型がP型ならホウ素あるいはニフッ化ホウ素を好ましくは1×1015atoms/cm2から1×1016atoms/cm2のドーズ量でイオン注入する。さらに、ここでのソース領域およびドレイン領域への不純物添加は、トレンチ6を有しない同一チップ内のMOSトランジスタと同一条件で同時におこなうことが可能である。その後、図2(F)に示すように、800℃〜1000℃で数時間熱処理することで、ソース高濃度拡散層9およびドレイン高濃度拡散層10を形成させる。以上で第2導電型埋め込み層2とトレンチ6を有するMOSトランジスタが製造される。
Next, as shown in FIG. 2D, a polycrystalline silicon gate film is preferably deposited to a thickness of 100 nm to 500 nm, and an impurity is introduced by predeposition or ion implantation to form the
図3(A)は第2の実施例の半導体装置を示す模式図である。実施例1でも説明したように、トレンチ6と第2導電型埋め込み層2との位置関係は、トレンチ6側面の端部Gが第2導電型埋め込み層2の側面の端部Fより内側であることが望ましいが、ソース高濃度拡散層下端およびドレイン高濃度拡散層下端から第2導電型埋め込み層2までの距離Hがゲート長L'と同等以下の長さであれば、トレンチ6の底部の電流経路を優先的に電流が流れることになる。よって、トレンチ6側面の端部Gが第2導電型埋め込み層2の側面の端部Fより外側であっても、ソース高濃度拡散層下端およびドレイン高濃度拡散層下端から第2導電型埋め込み層2の側面の端部Fまでの距離Hがゲート長L'と同じかそれより短いという条件を満たせば、トレンチ6の底部にも電流が流れ、駆動能力が向上する。
FIG. 3A is a schematic diagram showing the semiconductor device of the second embodiment. As described in the first embodiment, the positional relationship between the
図3(B)はトレンチ6の長さと第2導電型埋め込み層2の長さが同じに形成されており、トレンチ6側面の端部Gが第2導電型埋め込み層2の側面の端部Fが同一直線状に揃っている態様を示している。この場合でもソース高濃度拡散層下端およびドレイン高濃度拡散層下端から第2導電型埋め込み層2までの距離Hがゲート長L'と同じかそれよりも短いという条件を満たせば、トレンチ6の底部にも電流が流れ、駆動能力が向上する。
3B, the length of the
以上説明したように、トレンチの底部に埋め込み層を設け、ソース高濃度拡散層およびドレイン高濃度拡散層と埋め込み層との距離を、ゲート長と同じかそれより短くすれば、トレンチ底部にも電流が流れ、半導体装置の駆動能力が向上する。 As described above, if a buried layer is provided at the bottom of the trench and the distances between the source high-concentration diffusion layer and the drain high-concentration diffusion layer and the buried layer are equal to or shorter than the gate length, the current also flows in the trench bottom. This improves the driving capability of the semiconductor device.
1、11 第1導電型半導体基板
2 第2導電型埋め込み層
3 第1導電型エピタキシャル成長層
4、12 LOCOS酸化膜
5 マスク
6、13 トレンチ
7、14 ゲート絶縁膜
8、15 ゲート電極
9、16 ソース高濃度拡散層
10、17 ドレイン高濃度拡散層
F 第2導電型埋め込み層の側面の端部
G トレンチ側面の端部
L、L' ゲート長
DESCRIPTION OF
Claims (7)
前記第1導電型半導体基板上の所定の領域に形成された第2導電型埋め込み層と、
前記第2導電型埋め込み層および前記第1導電型半導体基板の上に形成された第1導電型エピタキシャル成長層と、
前記第1導電型エピタキシャル成長層に形成された、形成されるトランジスタのゲート幅方向に並んで配置された、その底部は前記第2導電型埋め込み層に達するトレンチと、
ゲート絶縁膜を介して前記トレンチの内部及び上面と前記トレンチに隣接する第1導電型エピタキシャル成長層の表面部分に形成されたゲート電極と、
前記ゲート電極の一方の側に形成された第2導電型のソース高濃度拡散層と、
前記ゲート電極の他方の側に形成された第2導電型のドレイン高濃度拡散層と、
を有する半導体装置。 A first conductivity type semiconductor substrate;
A second conductivity type buried layer formed in a predetermined region on the first conductivity type semiconductor substrate;
A first conductivity type epitaxial growth layer formed on the second conductivity type buried layer and the first conductivity type semiconductor substrate;
A trench formed in the first conductivity type epitaxial growth layer, arranged side by side in the gate width direction of the transistor to be formed, and a bottom portion of the trench reaching the second conductivity type buried layer;
A gate electrode formed on the inside and upper surface of the trench and a surface portion of the first conductivity type epitaxial growth layer adjacent to the trench via a gate insulating film;
A second conductivity type source high-concentration diffusion layer formed on one side of the gate electrode;
A second conductivity type drain high concentration diffusion layer formed on the other side of the gate electrode;
A semiconductor device.
前記第2導電型埋め込み層および前記第1導電型半導体基板の上に第1導電型エピタキシャル成長層を形成する工程と、
前記第1導電型エピタキシャル成長層に、形成されるトランジスタのゲート幅方向に並んで、その底部が前記第2導電型埋め込み層に達するようにトレンチを形成する工程と、
ゲート絶縁膜を形成する工程と、
前記ゲート絶縁膜を介して前記トレンチの内部及び上面と前記トレンチに隣接する第1導電型エピタキシャル成長層の表面部分にゲート電極を形成する工程と、
前記ゲート電極の一方の側に第2導電型のソース高濃度拡散層、他方の側に第2導電型のドレイン高濃度拡散層とを形成する工程と、
を含む半導体装置の製造方法。 Forming a second conductivity type buried layer in a predetermined region of the first conductivity type semiconductor substrate;
Forming a first conductivity type epitaxial growth layer on the second conductivity type buried layer and the first conductivity type semiconductor substrate;
Forming a trench in the first conductivity type epitaxial growth layer so that the bottom of the first conductivity type epitaxial growth layer reaches the second conductivity type buried layer in the gate width direction of the transistor to be formed;
Forming a gate insulating film;
Forming a gate electrode on the inside and upper surface of the trench and the surface portion of the first conductivity type epitaxial growth layer adjacent to the trench through the gate insulating film;
Forming a second conductivity type source high-concentration diffusion layer on one side of the gate electrode and a second conductivity type drain high-concentration diffusion layer on the other side;
A method of manufacturing a semiconductor device including:
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